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First direct determination of the Boltzmann constant by an optical method

Christophe Daussy·Mickael Guinet·Anne Amy-Klein·Khelifa Djerroud·Yves Hermier·Stephan Briaudeau·Christian J. Bordé·Christian Chardonnet
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Abstract

We have recorded the Doppler profile of a well-isolated rovibrational line in the \nu2 band of 14NH3. Ammonia gas was placed in an absorption cell thermalized by a water-ice bath. By extrapolating to zero pressure, we have deduced the Doppler width which gives a first measurement of the Boltzmann constant, kB, by laser spectroscopy. A relative uncertainty of 2x10-4 has been obtained. The present determination should be significantly improved in the near future and contribute to a new definition of the kelvin.

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Christophe Daussy, Mickael Guinet, Anne Amy-Klein, Khelifa Djerroud, Yves Hermier, Stephan Briaudeau, Christian J. Bordé, Christian Chardonnet. 2007-01-24. First direct determination of the Boltzmann constant by an optical method. https://doi.org/10.1103/physrevlett.98.250801

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